Genetic diversity of phthalic acid esters-degrading bacteria isolated from different geographical regions of China.

Thirty-two strains of phthalic acid ester (PAEs)-degrading bacteria were isolated from thirteen geographically diverse sites by enrichment using mixtures of PAEs as the sole source of carbon and energy. Sequence analyses of the 16S rRNA gene indicated that these isolates were from six genera (Arthrobacter, Gordonia, Rhodococcus, Acinetobacter, Pseudomonas, and Delftia). To evaluate the genetic diversity among them, the molecular typing method rep-PCR with primers based on enterobacterial repetitive intergenic consensus, repetitive extragenic palindromes, and BOXAIR sequences was performed. Strain-specific and unique genotypic fingerprints were distinguished for most of these isolates. In addition, utilization of various PAEs and the central intermediate phthalic acid by representative isolates suggested inter-isolate differences in the substrate utilization and degradation pathways. Furthermore, HPLC analysis showed that the rate of dimethyl phthalate degradation varied from 48.32 to 100% between strains. These results suggest a high level of genetic diversity among PAEs-degrading bacteria in the natural environment and their great potential to clean up phthalates-contaminated environments.